Implantable polymer for bone and vascular lesions

Abstract

A solidifying prepolymeric implant composition comprising a biocompatible prepolymer and an optional filler. One such implant composition is a polyurethane implant composition comprising an isocyanate, such as hydroxymethylenediisocyanate (HMDI) and an alcohol, such as polycaprolactonediol (PCL diol). The compositions of the invention are useful for improving bone structure in patients by applying the solidifying implant composition to bone, reinforcing bone structure, improving load bearing capacity and / or aiding healing of microfractures.

Description

REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of International Application PCT / US2011 / 057124 filed Oct. 20, 2011 entitled “IMPLANTABLE POLYMER FOR BONE AND VASCULAR LESIONS” which claims the priority of U.S. Provisional Patent Application No. 61 / 394,968 filed Oct. 20, 2010 also entitled “IMPLANTABLE POLYMER FOR BONE AND VASCULAR LESIONS”, each of which is incorporated herein in their entirety by reference.BACKGROUND OF THE INVENTION[0002]1. Technical Field[0003]The present invention relates to compositions and methods of treating bone fractures. In particular, the present invention relates to compositions made of polymers and ceramics for treating bone fractures, lesions, voids, and temporary or permanent fixation of implants. Additionally, the present invention relates to compositions made of polymers for treating vascular lesions and visceral fistulas.[0004]2. Background Art[0005]Progressive loss of bone density and thinning of bone tissue are c...

AI Technical Summary

Benefits of technology

[0027]In some embodiments, the solidifying implant composition can be a solidifying polyurethane composition comprising an isocyanate, such as hydroxy-methylenediisocyanate (HMDI) and an alcohol, such as polycaprolactonediol (PCL diol). The compositions of the present invention are useful for treating patients by applying the solidifying implant composition to bone, reinforcing the bone structure, improving load bearing capacity and / or aiding healing of microfractures.

[0034]The present invention provides for a method of treating bone structures such as a fracture or other bone defect site in a patient by injecting the prepolymeric implant composition to bone (optionally mixed together with a filler, crosslinking agent or a biocompatible solvent). This reinforces the bone structure, improving load bearing capacity and aiding healing of microfractures.

Problems solved by technology

Although regular exercise with daily intake of vitamin and mineral supplements can help alleviate the symptoms of osteoporosis, they do not provide wholesome treatment to those experiencing osteoporosis-induced fractures.

Although these medications and routine changes can help prevent fractures, it cannot reverse pre-collapsed vertebrae, or regenerate large quantity bone defects created by trauma, infection, skeletal abnormalities or tumor resection.

Although these clinical procedures allow the patient to regain functional abilities without pain, they carry various risks with them as well, including: risk of infection, risk of orthopedic cement leakage out of vertebral body that can cause pulmonary edema if cement migrated to the lungs, secondary fracture of the adjacent vertebra if cement leaks into the disk space, and neurological symptoms if cement leaks onto spinal nerves.

The most common problem that arises from osteoporosis-induced fractures is failure of fixation of the aforementioned screws, metal plate, or rod due to the decreased bone density in the osteoporotic patient.

This population can be particularly difficult to treat since, after treatment, the patient is more likely to put significant tension on the bone due to a higher level of activity than with an older and / or more sedentary patient.

The disadvantage of current PMMA based bone cements are their physical properties, lack of osteoconductivity, and resorption.

This prevents the PMMA from being properly integrated into the bone, and instead, the PMMA is encapsulated by a connective tissue layer.

This can lead to a revision surgery.

The difficulty and length of the revision surgery is increase by the difficulty in removing current bone cements.

The disadvantage of PMMA infused with various salt additives has similar disadvantages as aforementioned for sole PMMA based bone cements.

The main disadvantage of calcium phosphate and other ceramic cement based bone substitutes is their low tensile strength.

This limits their ability to be used in any location where there is a tensile component of the loading on the bone, such as on long bones such as the tibia.

Their thicker viscosity is an additional limitation.

This limits their ability to be pushed though small lumen used in minimally invasive treatment and percutaneous injections.

The disadvantage of bioactive glass substitutes includes, but is not limited to, poor resorption in natural bone.

Although bioactive glass substitutes possess superior mechanical strength, varying pore sizes between 50-150 microns, and high connectivity between pores, the substitute has a poor resorption rate, and therefore, the natural bone has hindered growth.

Similar to the ceramic cements the glasses have very poor tensile properties.

There are several challenges with current liquid embolic technologies.

Currently, there are not effective treatments available or available treatment options are dangerous, painful, and debilitating.

The available methods for endovascular treatment of vascular lesions are often ineffective and require numerous re-treatments.

The buildup of radioopaque material from multiple injections, large injections, or subsequent embolization procedures makes imaging and safely navigating the vascular lesion more difficult, takes longer, and limits the imaging options.

Difficulty visualizing the vascular lesion leads to increased procedural times, radiation dose to the patient and surgical staff, and treatment cost.

Patients frequently get radiation bums and lose hair from the prolonged exposure.

Current devices approved for treatment and / or occlusion of venous varices, vascular tumors, and traumatic vessel injury are awkward to handle, lack control, and are often incomplete or require multiple treatments.

More invasive and dangerous treatment with open neurovascular surgery or single, high dose stereotactic radiation (which may be incompletely effective, or require a significant therapeutic interval during which the patient is not protected from cerebral hemorrhage) can be required for these patients who cannot be completely and durably treated by minimally invasive methodologies.

Endovascular devices and surgical repair of aneurysms may not completely and durably occlude certain lesions and may require retreatment.

The solvent volume used in current liquid embolic agents is not safe or compatible for many procedures.

This was demonstrated when Onyx did not meet the FDA requirement of a USP 7-day muscle implant evaluation because implantation resulted in an acute tissue response.

Making visualization difficult for the surgeon and causing pain for the patient.

These procedures are converted to an intubated procedure increasing the risk and cost of the treatment.

DMSO ability to lower the vagal threshold could be a cause of the bradycardia seen when using Onyx near the valgus nerve.

Open surgical treatment is dangerous, debilitating and more costly.

Currently, no optimal and safe device exists for endovascular treatment for many arteriovenous malformations, arteriovenous fistulae, or visceral and / or viscerocutaneous fistulae.

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